Heater Bypass System

The heater bypass system promotes transmission fluid flow through the transmission cooling system by heating the radiator in-tank transmission cooler prior to the engine thermostat opening. Insufficient radiator warming during cold weather operation will cause reduced cooler flow and result in transmission overheating and internal damage due to inadequate lubrication. For vehicles operating in areas where the outside temperatures fall below 0 degrees fahrenheit (-18 degrees celsius) the heater bypass system must be updated to the latest level.